High-Performance, Glass Stabilized, Microwave Frequency Sources

An ultrastable, low-noise, low-cost, fixed-frequency, S-band transistor frequency source controlled by a metallized glass cavity has been computer optimized. Frequency and temperature stabilities of 0.9 × 10-9 parts/hour and 1.8 × 10-7 parts/°C, respectively, have been achieved. A C-band, tunable, IMPATT diode frequency source with 8 × 10-8 parts/hour stability, excellent tuning accuracy, and a very clean frequency spectrum is also described. These results demonstrate that glass cavity-controlled frequency sources present a viable alternative to the more complex, expensive frequency synthesizer. This approach can also favorably provide tunable sources in the X-, Ku-, or Ka-band, and fixed-frequency sources using GaAs FET devices up to X-band.